def f1(x):
    return sum(i ** 2 for i in x)


def f5(x):
    dim = len(x)
    return sum(100 * (x[i + 1] - x[i] ** 2) ** 2 + (x[i] - 1) ** 2 for i in range(dim - 1))


def f6(x):
    dim = len(x)
    prod = 1
    for x_item in x:
        prod = prod * abs(x_item)
    return sum(abs(x)) + prod
